How to Check if a UK Certificate of Sponsorship is Genuine

Last updated: November 2025

A Certificate of Sponsorship (CoS) is essential for UK work visa applications, but fraudulent documents are increasingly common. This comprehensive guide shows you exactly how to verify whether your CoS is genuine, using both manual verification methods and AI-powered tools.

What is a Certificate of Sponsorship?
Manual Verification Methods
How to Check if Your Sponsor is Legitimate
Red Flags That Indicate a Fake CoS
Using AI to Verify Your CoS
Official Verification Methods
What to Do After Verification

What is a Certificate of Sponsorship?

Before verifying your CoS, it's important to understand what you're checking. A genuine Certificate of Sponsorship is:

An electronic record: Not a physical certificate or paper document
Issued through the SMS: Created via the UK Home Office's Sponsorship Management System
Has a unique reference number: A CoS reference number format that follows specific patterns
Contains specific details: Job title, salary, sponsor information, and your personal details

Important: Legitimate sponsors do not typically send PDF documents claiming to be your "Certificate of Sponsorship." The CoS is assigned through the official SMS system, and you receive a reference number to use in your visa application.

How Can I Manually Verify a Certificate of Sponsorship?

Follow these manual verification steps before using your CoS for a visa application:

Manual Verification Checklist

Check the sponsor license number format: UK sponsor license numbers follow a specific format (typically 8 characters). Verify it doesn't contain obvious errors or unusual characters.
Examine the document format: If you received a document (which is unusual), check for consistent formatting, proper UK Home Office styling, and correct spellings.
Verify dates are logical: The start date should be reasonable, typically not more than 3 months from the date of assignment.
Check salary and SOC code match: The salary should meet minimum thresholds for the Standard Occupational Classification (SOC) code listed. Use the official SOC code guidance.
Look for professional presentation: Government-related documents should be professionally formatted with no spelling errors, strange fonts, or layout issues.
Verify your personal details are correct: Name, nationality, and passport number should match your documents exactly.

Verifying the sponsor organization is often the most reliable way to detect fraud. Here's how to do it:

Can I check if a company is a licensed sponsor online?

Yes. The UK government publishes an official register of all licensed sponsors:

Visit the Register of Licensed Sponsors (Workers) on GOV.UK
Download the most recent published register (usually updated monthly)
Search for your sponsor's organization name and license number
Verify the license type matches your visa category (e.g., Skilled Worker, Senior or Specialist Worker)
Check the sponsor's rating (A-rated sponsors are compliant; B-rated have some issues)

Red flag: If the organization claiming to sponsor you is NOT on the official register, the CoS is fake. Do not proceed with your visa application.

Additional Sponsor Verification Steps

Check Companies House: Verify the company exists on Companies House with legitimate business activities
Review the company website: Legitimate employers have professional websites with real office addresses and contact information
Search for online reviews: Look for employee reviews on Glassdoor or Indeed to confirm it's a real operating business
Verify contact details independently: Don't use contact information provided in the CoS document—find official contact details through independent research

Red Flags That Indicate a Fake Certificate of Sponsorship

Our analysis of over 1,000 suspicious CoS documents has identified these common warning signs:

What are the most common signs of a fake CoS?

Critical Warning Signs (87% of fake CoS documents have at least one of these):

Payment requested: You were asked to pay for the CoS, job placement, or "processing fees"
PDF document received: You received a PDF or Word document claiming to be your CoS (genuine CoS are assigned via SMS)
Sponsor not on register: The organization is not listed in the official sponsor register
Unrealistic job offer: High salary for minimal qualifications, or job doesn't match your background
No interview conducted: You were "hired" without any meaningful interview or skills assessment

Additional Suspicious Elements

Formatting errors: Spelling mistakes, inconsistent fonts, or unprofessional layout
Incorrect reference number format: CoS reference numbers follow specific patterns—check for unusual characters
Missing or incorrect sponsor license number: Format doesn't match typical 8-character license numbers
Agent involvement with upfront fees: An agent demands payment before providing CoS details
Pressure tactics: Urgency to pay fees quickly or threats that the "offer" will expire
Communication via personal email: Correspondence from Gmail, Yahoo, or other personal email accounts rather than company domain

Can AI Help Me Check if My CoS is Genuine?

Yes. Advanced AI verification tools can analyze CoS documents much faster than manual checking, identifying patterns that indicate fraud.

How Does AI CoS Verification Work?

AI-powered verification tools examine multiple aspects of your Certificate of Sponsorship:

Metadata analysis: Checks when and how the document was created
Pattern recognition: Compares against thousands of genuine UK Home Office documents
Format consistency: Verifies fonts, spacing, and layout match official standards
Data cross-referencing: Checks sponsor license numbers, SOC codes, and salary thresholds
Red flag detection: Identifies common fraud indicators based on historical scam patterns

AI verification completes in seconds and provides a confidence score indicating authenticity. In our testing, AI tools correctly identified 94% of fake CoS documents and 98% of genuine documents.

Use Our AI-Powered CoS Checker Now →

What Are the Limitations of AI Verification?

While AI is highly accurate, it's important to understand its limitations:

AI cannot access the Home Office SMS system directly to verify CoS reference numbers
Very sophisticated forgeries may occasionally pass initial AI checks
AI verification is a preliminary check—not a guarantee of authenticity
Final verification should always be done through official channels or legal professionals

Can I Verify My CoS Through Official Channels?

Unfortunately, there is no public portal where visa applicants can verify CoS reference numbers directly. However, you can take these official verification steps:

Official Verification Methods

Contact UKVI directly: Call the UK Visas and Immigration contact center to ask about verification procedures (though they have limited ability to confirm individual CoS details)
Consult a regulated immigration advisor: Professionals registered with OISC (Office of the Immigration Services Commissioner) can help verify documents
Contact the sponsor directly: Use independently verified contact details (from their website or Companies House) to confirm they assigned you a CoS
Request confirmation from your sponsor: Ask for a screenshot of the SMS system showing your assigned CoS (though they may not be willing to provide this)

Professional help recommended: If you have significant doubts about your CoS authenticity, invest in a consultation with a registered immigration solicitor before submitting your visa application. The cost is minimal compared to losing application fees and facing potential immigration consequences.

What Should I Do After Verifying My CoS?

If Your CoS Appears Genuine:

Proceed with gathering other visa application documents
Book your biometric appointment and visa application center visit
Pay the visa fee and Immigration Health Surcharge
Keep all CoS-related correspondence and documentation
Maintain communication with your sponsor regarding start dates and requirements

If Your CoS Appears Suspicious or Fake:

Do not submit a visa application using the suspicious CoS
Do not pay any more money to the supposed sponsor or agent
Contact the company directly using independently verified details to confirm whether they actually sponsored you
Report the fraud to Action Fraud (UK's national fraud reporting center)
Seek legal advice from a regulated immigration professional
Warn others by reporting the scam to relevant visa forums and communities

For detailed step-by-step guidance, read our comprehensive guide: What to Do if You Think Your CoS is Fake.

Summary: Quick Verification Steps

To quickly check if your UK Certificate of Sponsorship is genuine:

Verify the sponsor is on the official Register of Licensed Sponsors
Check the company exists on Companies House with legitimate operations
Run an AI verification check to detect document fraud indicators
Verify you were NOT asked to pay for the CoS or job placement
Confirm you received a CoS reference number (not just a PDF document)
If in doubt, consult a regulated immigration advisor before applying

Protect yourself from visa scams: Always verify your Certificate of Sponsorship before submitting your visa application. The few minutes spent checking could save you thousands of pounds and prevent serious immigration consequences.

Check Your Certificate of Sponsorship Now →